The present invention relates to a solid-state light source device applying a solid-state element, such as, a light emitting diode or a semiconductor laser, etc., as a light source therein, attracting attentions thereon as a light source being superior in energy saving, and in particular, it relates to a solid-state light source device suitable for a projection-type display apparatus, modulating an intensity of the light from a light source depending on a video signal, by means of a light-transmission type or reflection type liquid crystal panel or a digital mirror device (DGD), which is built up with plural numbers of micro mirrors aligned, thereby projecting an optical image formed, enlargedly.
In recent years, as a lightening apparatus is used a light source, widely, applying the solid-state element, such as, the light emitting diode and/or the semiconductor laser, etc. therein, being superior in the energy saving, in the place of a conventional lamp and/or a fluorescent lamp. On the other hand, a projection-type display apparatus is already known in the following Patent Document, for example, which stores within a housing thereof, an optical unit, for modulating an intensity of the light from a light source depending on a video signal by means of light valves and thereby projecting an optical image formed, enlargedly, together with a driver circuit, power source circuits and/or a cooling fan, etc.
However, within such conventional projection-type display apparatus, for the purpose of maintaining a sufficient brightness on a projection surface, in particular, a super or ultra high-pressure mercury lamp having high efficiency per an electric power inputted (for example, 70 lm/W) is mainly applied as the light source thereof, normally, in a lighting optic system.
However, when applying a discharge lamp, generating a white light therefrom, it is necessary to provide a high-voltage power source, causing a difficulty in handling thereof, and also since it is short in the lifetime thereof and low in the shock-resistance thereof, therefore, in the place thereof, ideas or proposals are made, variously, of applying the solid-stake light source, such as, the light emitting diode and/or the laser diode, etc., as the light source of the projection-type display apparatus.
For example, in Japanese Patent Laying-Open No. 2002-268140 (2002) is proposed a projection-type display apparatus, disposing sheet-like light sources, each aligning light emitting diodes emitting a light, one of three (3) primary colors; i.e., red (R), green (G) and blue (B), in an array-like manner, behind a light modulator (i.e., the light valve) corresponding to R, G or B.
Also, in Japanese Patent Laying-Open No. 2004-341105 (2004) is already known a projection-type display apparatus, applying a light emitting diode for generating ultraviolet (UV) rays therefrom, being a solid-state light source, as the light source of the projection-type display apparatus, wherein those UV rays are irradiated on a color wheel, which is made from fluorescent substance layers of R, G and B, successively, thereby to converted them into R-light, G-light and B-light, and each of those color lights is projected, successively, through a space modulator, enlargedly by means of a projection lens, thereby displaying an optical image.
And, in Japanese Patent Laying-Open No. 2009-277516 (2009) is already proposed that applying a light emitting diode or a laser light emitting device for generating a light of blue (B) color, in the place of the light emitting diode for generating a light with using the UV rays mentioned above as excitation lights thereof, for the purpose of avoiding injury or damage due to the UV rays, and thereby maintaining a long life-time of optical parts. Further, in Japanese Patent Laying-Open No. 2009-259583 (2009) is disclosed the structure for dissolving shortage of an amount of lights from the light emitting diodes of green (G) color, in particular, in case where plural numbers of light emitting diodes are applied and the light rays emitted therefrom are condensed to be used. Thus, there is proposed a light source device having a third light source for composing a light (i.e., an excitation light) from the light emitting diode of B-color for the light from the light emitting diode of G-color, by means of a dichroic mirror, and for passing the G-light therethrough, and being excited by absorbing the B-light, thereby generating the G-light.